PACHYTHELIA VILLOSELLA. 399 



line, a smaller dorsal one on the 1st abdominal. The head presents the 

 following details' — two eye-patches of pigment with neither compound 

 facets (imaginal) nor single ocelli (larval) ; antennas two- jointed, not 

 unlike larval antennae ; a large number of fine bristles on head ; two 

 maxillary prominence? not quite so prominent as legs. The legs are 

 transverse plates, with a chitinous tubercle, which has a small central 

 mammilla. No hairs in general on the segments, a few, however, on 

 the 8th and 9th abdominals, and very numerous but very minute ones 

 on ovipositor (Butterfield). At first sight the ? of P. villosella (and 

 of other Psychids) is very chaotic and puzzling, but a little examination 

 shows the head with its eye-spots (sunk), antennae, labral and labial 

 prominences. The three thoracic segments each larger than the pre- 

 ceding, with dorsal black plates each smaller (proportionally) than the 

 preceding one, each with transverse ridges ventrally carrying the legs, 

 each leg being an oval plate with a central mammilla and point, the 

 posterior being the larger. The prothoracic spiracle at, or just below, 

 the margin of plate, well-marked. The 1st abdominal segment shows a 

 dorsal plate, dark, but smaller than that of the last thoracic, and carries 

 a large spiracle ; it is rather narrow ventrally, as is also, in a consider- 

 able degree, the next one, which also has dorsally a chitinous plate 

 (but a small spiracle), and is almost without colour. The abdominal 

 segments 3-7 are more uniform in width, large, white, or colourless, 

 and each carries a spiracle. Each of these seven abdominal segments 

 has (as also the thoracic) a double brown ganglion, very conspicuous, 

 ventrally, that of the 7th segment, apparently, from its size and out- 

 line, including that of the 8th segment also. The 8th abdominal segment 

 is very conical, tapering rapidly, anally narrower than the others, and 

 narrower ventrally, and has no spiracle or ganglion. The 9th abdominal 

 segment is a narrow and altogether small segment, carrying, ventrally, 

 a curious double lappet, the precise nature and function of which 

 sexually are not clearly evident. The 10th segment forms a small 

 tapering (?) ovipositor (Chapman, June 17th, 1899). The ? of P. 

 villosella is longer (8-9 lines long) and, in comparison, more slender than 

 those of Ptilocephala angastella (atra) and Psyche viciella. The head is bent 

 inwards, yellow-brown, with short white antennal stumps and black eye- 

 spots. The three thoracic plates are brown, and on the back of the 4th 

 segment is also a small brown corneous spot of irregular form. The 

 colour of the body and the three pairs of legs is yellowish -white. The 

 corneous plates of the last three segments are of a light brown colour 

 (Hofmann) . 



Vakiation. — The species (owing to the coloration of the male) 

 cannot be a variable one, yet differences of size and tint appear 

 sufficiently defined to have developed several local races. This has 

 led Standfuss to assert that the moth varies much, and he states that 

 the Silesian examples differ considerably from the south German ones, 

 the fore- and hindwings being narrower, the colour grey-black instead 

 of the decided brown of the south German examples, whilst sometimes 

 the nervures six and seven are stalked instead of seven and eight, but 

 transitions between the two forms occur. The following appear to be 

 the various forms described, some possibly not really forming local 

 races apart from the type. 



a. var. nigricans, Curt., "Brit. Ent.," v., pi. 213 (1828); Stphs., "111. Brit. 

 Ent.," ii., p. 79 (1828); " Cat.," p. 57 (1829); " List An. Brit. Mus.," v., p. 55 (1850); 



